1. Field of the Invention
The present invention relates to adhesive patches suitable for use for dressings, such as medical dressings for covering a portion of the anatomical surface of a living being, or, in particular, for use as adhesive barrier member for ostomy appliances, a method for preparing such adhesive patches, and methods of treating a portion of the anatomical surface of a living being, especially a protruding part of the body, and for applying an ostomy appliance comprising such adhesive patch.
In connection with surgery for a number of diseases in the gastrointestinal or urinary tract a consequence is, in many cases, that the colon, the ileum or the ureter has been exposed surgically and the patient is left with an abdominal stoma, or, in nephrostomy or ureterostomy, the ureter or a catheter is exposed in the back or the chest region or abdominal region, and the effluents or waste products of the body, which are conveyed through these organs, are discharged through the artificial orifice or opening and are collected in a collection bag, which is usually adhered to the skin by means of an adhesive wafer or plate having an inlet opening for accommodating the stoma/ureter/catheter. Also in connection with a fistula, the patient will have to rely on an appliance to collect the bodily material emerging from such opening.
Ostomy appliances are well known. Such appliances may be two-piece or one-piece appliances. In both types of appliances, an adhesive barrier member or base plate is attached to the wearer's abdomen/back/chest. In case of a one-piece appliance, a receiving member or bag is attached to the base plate. In case of a two-piece appliance, the adhesive base plate forms part of a body side member and a receiving member or bag is attached releasably to the body side member for receiving exudates from the stoma.
When using one-piece appliances, the whole appliance, including the adhesive skin barrier securing the appliance to the skin is normally removed and replaced by a fresh appliance. When using two-piece appliances, the body side ostomy member is left in place up to several days, and only the receiving member or bag attached to the body side member is replaced.
Conventionally, dressings for the treatment or prevention of wounds or pressure sores or even unbroken skin are essentially flat dressings, which are sufficiently mouldable to be applied to flat or slightly curved areas of the body. Such flat dressings are not very suitable for applying on protruding parts of the body such as joints e.g. heels or especially elbows or knees having not only a very pronounced curvature but also being subject to constant bending which often causes wrinkling and focusing of stresses in the dressing often causing release of the adhesive and unintended detachment of the dressing.
When an ostomy appliance is placed on the abdomen of a user, the bandage has to follow the movements of the skin caused by physical activity as the user would else have a feeling of carrying a very inflexible product, or the appliance might lose its hold of the skin.
The physical activity and change of positions of the user give rise to a bending, stretching, or upsetting of the appliance. The first attack will be concentrated at the borderline between uncovered skin and skin covered by the appliance. When stretching is caused at this borderline, several events/things may happen.
If the appliance is sufficiently flexible, this effect will hardly be noticed by the user. If the flexibility of the appliance is insufficient to take up the stretching, bending and upsetting, and the adhesion to the skin is maintained, the user will notice the effect and will eventually experience a pain or itching under the appliance. If the adhesion to the skin is broken, the appliance will loosen from the skin and eventually cause a leakage.
2. Description of the Related Art
Flexibility of an ostomy appliance may be obtained in several manners. The appliance may be made very thin and having a flexible carrier sheet but a very thin layer of adhesive will due to the low mass not show a sufficient absorbing capacity to uphold an acceptable service time for the appliance. If a high absorbing capacity is desired, the thickness of the adhesive layer may be increased causing a loss of flexibility of the appliance. In this case one way to preserve the flexibility is to provide embossing or indentations in the product providing areas in which the adhesive layer is thinner. The flexibility is then obtained as the thinner areas easier yield on applied forces conserving the absorption capacity of the thicker product.
Thus, WO 93/00056 discloses that a skin-friendly dressing having grooves or ditches fully or partly surrounding a central part of the dressing has a high degree of flexibility.
EP patent No. 0 768 071 discloses a wound dressing especially for use in the sacrum area, said dressing having one or more linear depressions that assist a user in applying, flexing or folding the dressing and that the dressing may have two sets of spaced parallel depressions forming a grid which is useful in the wound assessment. The thickness of the adhesive layer at the base of the depressions should at least be as great as the thickness of the border portion of the adhesive layer.
GB patent No. 1,075,939 discloses an adhesive bandage having a thermoplastic top film provided with embossments in order to allow passage of water vapour though the film.
Published EP patent application No. 0 256 893 discloses a non-adherent dressing comprising a film which contains depressions over the wound contacting area which depressions contain a viscous pharmaceutical composition which is suitable for topical application. The depressions may be in the form of a pattern of conical depressions.
GB patent No. 1,075,939 and EP patent application No. 0 256 893 are silent with respect to flexibility.
WO 99/36017 discloses a dressing comprising a substantially water-impervious layer and a skin-friendly adhesive having a pattern of indentations, which diminishes or disappears when the dressing is moisturised. The grooves are stated to have a depth of at least 25% and more preferred at least 50% of the thickness of the dressing and it is stated that the pattern may increase the flexibility of the dressing.
The publications do not disclose the problems associated with formation of wrinkles or folds during use of a wound dressing or an ostomy appliance, which may lead to formation of canals causing risk of leaking of obnoxious smells or soiling from aggressive exudates.
Furthermore, it has been found that the flexibility of a dressing or adhesive barrier member of an ostomy appliance is important, with respect to the shape, the size and the adhesive of the dressing, not only in use but also during the application. When applying a dressing on a joint that is frequently bent, or when applying an ostomy appliance to an uneven of folded abdomen, flexibility becomes very important as the dressing or ostomy appliance must be able to adapt to the contour of the skin surface.